25% or 1/4 chance
Step-by-step explanation:
When crossing these two heterozygous parents, you will get the phenotype 3:1. This means...
75% chance of plant being tall
25% chance of plant being short
Since T is dominant and we are using simple Mendelian inheritance, the heterozygous offspring (Tt) will be tall as well.
This means there is a 25% or 1/4 chance of the plant being short.
~Punnett square and work below for you.